Atherosclerosis is a vessel disease which can cause stroke or heart attack. This disease gradually progresses over time if not treated. As a result, this disease progression needs to be monitored. There are several modalities which can be used for understanding the regression and progression of plaque in carotids, coronaries, aorta and other blood vessels. Some the most popular modalities are Magnetic Resonance Imaging (MRI) and Ultrasound.
The state of Atherosclerosis in carotids or other blood vessels can be studied using MRI or Ultrasound. Because ultrasound offers several advantages like real time scanning of carotids, compact in size, low cost, easy to transport (portability), easy availability and visualization of the arteries are possible, Atherosclerosis quantification is taking a new dimension using ultrasound. Because one can achieve compound and harmonic imaging which generates high quality images with ultrasound, it is thus possible to do two-dimensional (2D) and three-dimensional (3D) imaging of carotid ultrasound for monitoring of Atherosclerosis.
In recent years, the possibility of adopting a composite thickness of the tunica intima and media, i.e., an intima-media thickness (hereinafter referred to as an “IMT”) of carotid arteries, as an index of judgment of arterial sclerosis has been studied. Conventional methods of imaging a carotid artery using an ultrasound system, and measuring the IMT using an ultrasonic image for the purpose of diagnosis are being developed.
A conventional measuring apparatus can measure an intima-media thickness of a blood vessel using an ultrasound device to scan the blood vessel. Then, for example, an image of a section of the blood vessel including sections of the intima, media and adventitia is obtained. The ultrasound device further produces digital image data representing this image, and outputs the digital image data to a data analyzing device.
The intima, media and adventitia can be discriminated on the basis of changes in density of tissue thereof. A change in density of tissue of the blood vessel appears as a change of luminance values in the digital image data. The data analyzing device detects and calculates the intima-media thickness on the basis of the changes of luminance values in the digital image data. The digital image data can include a plurality of luminance values each corresponding to respective one of a plurality of pixels of the image. The data analyzing device can set a base position between a center of the blood vessel and a position in a vicinity of an inner intimal wall of the blood vessel on the image, on the basis of a moving average of the luminance values. The data analyzing device can detect a maximum value and a minimum value from among the luminance values respectively corresponding to a predetermined number of the pixels arranged from the base position toward a position of an outer adventitial wall on the image. The data analyzing device can then calculate the intima-media thickness on the basis of the maximum value and the minimum value.
Usually, the clinical data gathered from the analysis of IMT in patients are never reused when generated in clinics or hospitals. Examples of this clinical data can include images obtained after ultrasound scanning the diseased or abnormal anatomies, such as blood vessels or other organs. The disease can be Atherosclerosis (or plaque) deposits in the carotid arteries, which causes stroke or heart attack. The risk biomarker for such a disease is the intima-media thickness of the blood vessels in the carotids. The media-adventitia carotid wall is specifically challenging to detect due to the presence of plaque and speckle distribution. But, the clinical data is typically discarded after the diagnosis and/or treatment of a particular patient.
Thus, a system and method for creating and using intelligent databases for assisting in intima-media thickness (IMT) measurements is needed.